The present invention is related to a valve position indicator for providing a visual indication of the open or closed position of a valve.
Valves are used in subsea xmas trees to control the flow of oil and gas from subsea wells. In substantial water depths, these valves are typically actuated either hydraulically from a surface vessel or directly by a remote operated vehicle (ROV). In either case, it is important for the operator to have visual confirmation that the valve is in its open or closed position to ensure that the valve is functioning properly.
In certain prior art designs, such a visual indication is provided by a "flag" which is connected through a series of linkages to a threaded drive which in turn is coupled to the valve stem. Thus, when the valve is either opened or closed, the valve moves the flag either into or out of a "window", e.g. a hole formed in the ROV panel, to provide the necessary indication of the position of the valve. However, this design is somewhat complex and consequently difficult and expensive to manufacture.